Posted
by
Soulskill
on Wednesday October 05, 2011 @01:13AM
from the magnets-how-do-they-work dept.

brindafella writes "Thirteen years ago, two teams of astronomers and physicists independently made the same stark discovery: Not only is the universe expanding like a vast inflating balloon, but its expansion is speeding up. The two teams have now been recognized with the 2011 Nobel Prize in Physics. Half of the prize will go to Saul Perlmutter of Lawrence Berkeley National Laboratory and the University of California, Berkeley, who led the Supernova Cosmology Project. The other half will be shared by Brian Schmidt of the Australian National University's Research School of Astronomy and Astrophysics, who led the High-z Supernova Search Team, and Adam Riess of Johns Hopkins University and the Space Telescope Science Institute in Baltimore, Maryland, who worked on High-z. In essence, they proved that Einstein's 'biggest mistake' (the cosmological constant, to create a 'stable universe') was actually a clever theoretical prediction that there was something else happening — dark energy."

Not only are the galaxies going to fly apart but our solar system, the planets, our bodies, our cells and ultimately even our atoms (and subatomic particles!). I think only photons or other massless particles will be spared.:(

I know the Nobel committee said the Universe will end in Ice not Fire but it seems more like a great empty VOID.

So... is there a way to harness this "dark energy"? Like attaching a rope between two objects (planets?) and let the universe try to pull it apart? Or would the rope have to be massless? Or maybe there is a more direct way of harnessing this energy? (anti-gravity?)

Would it be less depressing to you if all ended in a Big Crunch? Why do we find a static universe pleasing? No birth without death.

Galaxies don't expand, so two planets wouldn't work as a way to harness dark energy. But the idea is that every cube of space, when you take out all the mass, still has some energy. Perhaps in form of tension or a pressure. So you wouldn't need to go far. But it is incredibly little. Although I should emphasize we don't know what it is yet, so we wouldn't even know how to start

Would it be less depressing to you if all ended in a Big Crunch?
The collapsing universe idea seemed sensible because it implied the universe was in an endless regenerative cycle. If it's just a one-shot deal, why is it happening now, of all times?

Consider: an electron near the edge of the visible universe still influences the electrons in by body to some tiny degree. One would expect the edge of the visible universe to be effectively an event horizon - nothing beyond the edge should be able to affect us here in any way. Yet it that electron "on the edge" is influenced by stuff "past the edge", and then eventually affects us, there is no event horizon, just a light horizon (which isn't real

The whole idea behind "dark energy" is that we don't know what it actually is or where it come from. So my guess is that until we know enough about it to put a better name on it, we won't do anything with it.

You're totally right as far as you go, but he's referring to "big rip" cosmologies, where ultimately (if you believe them hyper-literally, which is a bit suspect itself) the acceleration of the universe *vastly* overpowers gravitational bonds, and then electrostatic bonds, and then electroweak bonds and eventually strong bonds. And then there's a singularity.

It's possible to write a theory with a big rip, but they're pretty contrived and it doesn't look likely to me.

how does that effect things like the dark energy equations, if it effects them at all?

There are no 'dark energy equations', just standard physics applied to observational data.. Scientists have proved that the universe is expanding and that the expansion of the universe is accelerating based on observational data from a couple of different (you might say 'independent' if you don't try to be too philosophical about it) sources [wikipedia.org]. By running the data through standard physics equations they were able to calculate the magnitude of *an* energy that would be required to support that accelleration. T

All particles with positive mass go slower than the speed of light. Particles with zero mass go at the speed of light.Neutrinos, going faster than c like tachyons [wikipedia.org] have imaginary mass.Imaginary mass, plugged into gravitational formula which uses mass squared will give repulsion rather than attraction.If the universe is filled with these neutrinos, it would explain the repulsive force we label as dark energy.

Gravitaiton doesn't use mass squared, it uses the product of two different masses (at least Newtonian gravitation, GR doesn't directly use mass at all, only energy and momentum). So naively inserting an imaginary mass into Newton's gravitational force for both particles will indeed give repulsion (i.e. two imaginary masses would repulse each other). However putting in one imaginary and one real mass (to find out how tachyons interact with an ordinary mass) would give an imaginary force. I have no idea what

Imaginary mass, plugged into gravitational formula which uses mass squared will give repulsion rather than attraction.

If you're describing two imaginary masses. If you're describing an imaginary mass interacting with a real mass, you have an imaginary gravitational force. Given that all interactions between dark matter and normal matter would be of this nature, that's kind of a defect in your idea.

You got modded +1 for statements like "we CAN travel to the stars" and "the Universe is probably infinite, and that we have the power to shape the future of the Universe, because we are the Universe", "If we went Manhattan-Project style on the idea of going to the stars, we'd be there in no time" and "Scientists are just people who like to shit on the hearts of Engineers"?

That +1 was "funny" and he got a -1 troll. No karma for a "funny". I can't figure out if he was modded by scientists or engineers or thirteen year old kids. He's AC so maybe he logged out and commented, then logged on and modded himself down?

It means what we've all known and been thinking. That this "Dark Matter" and "Dark Energy" stuff is all baloney. It means that we DO have control of our destiny and that we CAN travel to the stars. It means that the Universe is probably infinite, and that we have the power to shape the future of the Universe, because we are the Universe.

If we went Manhattan-Project style on the idea of going to the stars, we'd be there in no time.

Wait, don't you have to be right first?

Here, you're all ready to start colonizing the galaxy, but we're missing the most important part: a phenomenon that would let us travel much faster than the speed of light. It makes no sense to fire up the project without the loophole already in mind.

The current experimental approach for high energy colliders is actually rather efficient IMHO for finding FTL phenomena. It's like have a vast field with one or more divots in the field. You could painstakingly go ov

No no no you see you make everything out of neutrinos! That way you can get where you're going a couple of days faster than light, which *obviously* opens the universe to exploration because it would only take you about four years to get the nearest star! Building everything, including yourself, out of neutrinos is just an engineering problem and those mighty engineers are just being held back by us pathetic weedy little killjoy fucking PHYSICISTS. Fuck those physicists.

I read the sad story of a bitter failure who's full of shit. Let's see you brute force yourself a 1m accuracy GPS system without Einstein. You can do it. You'd just be the latest in a long line of mule-headed engineers going back to Ptolemy. What, it's not accurate enough? Let's throw on another epicycle (correction fit to the residual). Still not accurate? Another epicycle (correction fit to the residual of the residual). Kepler and Einstein are full of shit, we'll just brute force it, right? You wan

Wannabe nerds that act as the working hands of science will just out anybody as an idiot if someone dare says that the Lorentz Factor is a load of horse shit. They want to tie velocity and gravity together, whenever the recent experiment breaking the light speed barrier throws all of that away.

To Anonymous,

Oh dear, Mr. Coward, just when my self-esteem was starting to recover, now I'm a wannabe nerd, a "working hand of science". Sigh. Well, my duty is clear -- your brilliant comment has shown me what

(whatever the hell that is -- I know what the Lorentz Transformation is, I know what O(1,3) is, I know what a Lie algebra is, but "Lorentz Factor" -- capitalized, no less -- I can only assume that you mean \gamma)

Yeah, I was kidding, I knew that. But the point is/was that \gamma isn't the LT, (and doesn't require dual capitalization) and to the extent that one writes kiddy-physics-wise L' = L/\gamma or t' = \gamma t for simple length contraction or time dilation instead of writing a proper LT using e.g. the boost parameter and hyperbolic 4-rotations it does work and work quite well, to describe things like ground level mu meson flux. That's an easy one because to measure it requires two good sized photomultipliers

"The empirical evidence could yet be interpreted in the context of the existence of accumulating carbon dust,"

No, it couldn't, there have been plenty of studies on the effect of dust on light propagation and it simply doesn't explain the observations.

"the evolution over history of the supernovae concerned - their increasing content of metals and their increasing spin as time progresses."

True, the progenitors aren't that well understood. This is usually treated as a systematic error in the surveys. The use of SN1a as standard candles is still somewhat controversial, which is why these days I always advocate leaving out the supernova datasets completely, in favour of observations of the CMB and of large-scale structures and the baryon acoustic oscillations in particular. Those two datasets combined give us a universe with about 25% dark matter, 70% dark energy, and 5% normal matter. The fact that the supernovae *also* happen to intersect at basically that exact same part of the plots is pretty suggestive that the systematics aren't very significant, though.

"The mathematical model rates as an embarrassment from the perspective of my criticism of fundamental physics."

This would be your famous criticism of fundamental physics that has received such attention? What criticism of fundamental physics? Do you fancy explaining why you think the mathematical model is an "embarrassment" or are you simply trolling? (I happen to think that the model is being over-interpreted since it's ultimately phenomenology - but it's startlingly successful for a phenomenological theory, and predictions have been tested against observation with a lot of success. The BAOs serve as a nice example of that.

"Together with a possible background of negative tachyonic mass, which is conserved in its direction of propagation."

And what the flying fuck is that meant to mean? Yeah yeah tachyons with negative mass. So, what, they lose mass perpendicular to their direction of motion? Kind of like a bird flying in a storm? How about you write a sensible theory and try and get it past all the standard tests.... no, wait, you won't.

"... the effect of dust on light propagation... simply doesn't explain the observations."But no term at all for this is included in the analysis. Long nano fibers would have an unfocused influence on the measurements.

"... why [do] you think the mathematical model is an "embarrassment" or are you simply trolling?"The cosmological constant and many other representations of dark energy are ruled out by the Bianchi identities that apply. This becomes plain when when the proper tensor rank is used for the space

1: Are you suggesting that the cosmos is filled with "long nano fibers"? Feel free to model it (properly), write it up rigorously and put it onto the arxiv; I'm sure people would read it. How "long" are you talking? What's the production mechanism? Or are they left behind by alien civilisations...? And yes, terms considering the dust *are* included in analyses. Generally they'll be bundled into systematic errors. There have also been numerous dedicated studies into the effects of dust. (Besides, I'm always

The Einstein tensor is taken to be second rank for no other reason but convention.

Careful consideration makes it out to be fourth rank covariant, so that it is a "geometric object" with no artificial entanglement with the metric added in after the natural derivation. The requirement that a tensor be drawable, and that problems can be worked correctly on this drawing independent of changes in scale and sparseness, is one of the many corollary forms of general covariance. Artificial entanglement with the metr

Step two is figuring out what that something is, and/or how it works. That's what we're* working on now.

Then comes application of that knowledge.

Einstein's Field Equations back around the first World War might have seemed awfully cryptic, but they led to quantum physics, which led to semiconductors, which led to Slashdot. (Okay, I may have skipped a step or two.)

So maybe in another 100 years, this dark energy stuff will actually lead to somethi

Actually, EFE have nothing to do with quantum physics - they're purely classical. Schrodinger/Heisenberg is where you want to really look for quantum physics (or the photoelectric effect, also an Einstein thing but nothing to do with the field equations).

That's not to say that EFE aren't awesome - they gave us the tools we needed for GPS etc, and tons of insight into cosmology, but technologically speaking we wouldn't be far behind if we still had a Minkowski space + Quantum Field Theory version of physics

We should just call what we have Ptolemaic Cosmology. We have no idea what the heck is going on. What we know is good enough for the technology we have. Dark matter and dark energy are just our versions of the epicycles. Convent for expressing what we see but no basis in reality.

Dark matter and dark energy are just our versions of the epicycles. Convent for expressing what we see but no basis in reality.

You can only be confident about something like that if you're incredibly impatient, and don't know much about how hard this stuff is. The earliest observational evidence of dark matter came from the 1930s, when Fritz Zwicky measured the line-of-sight velocities of galaxies in clusters and realized that there had to be more mass in clusters than could be attributed to the galaxies alone, or there wouldn't be enough gravity to keep them together as a cluster. It was another 30+ years later that we observed with X-ray telescopes a decent-sized chunk of that missing mass in clusters, in the form of a hot intracluster plasma at temperatures of tens of millions of degrees that fills the space between galaxies in clusters and, in rich clusters of galaxies, contributes several times more mass to the cluster than the galaxies within it. Thirty-plus years, for something that's fairly easy to see once you have the technology that can look there (X-ray telescopes); it took us a while to get it.

All our cosmological theories may turn out to be complete crap. But it's absurd to say so now on the basis of complaints like 'we haven't solved the dark matter problem yet' or 'we can't explain a nonzero vacuum energy.' There was a fair amount of time between Oersted and Maxwell, as well. In the meantime, the most plausible theories will get pursued, and we'll see.

It's not that we haven't solved the dark matter problem. It is that we speak of an imaginary construct erected to save an accepted model as if that imaginary construct is real. Saying that we really don't know what is going on is not impatience or fundamental lack of awareness of what scientific knowledge is. It is recognition that the Big Bang explanation has some fundamental challenges and we have to turn to imaginary matter and imaginary energy to continue to cling on. Epicycles actually predicted the ap

Dark energy is the name of a problem, not a solution. It's embarrassing that 75% of the universe is made up of we-have-no-idea-what.

Dark energy is the anonymous coward of particle physics. If it would sign up for a proper account, it would be far easier to study. It's possible that we already understand dark energy completely: a term that shows up in a few things we already measure, with no additional personality to be further described.

I get that this is the Nobel prize - but these people appear to have already accomplished something. Indeed, the noteworthy achievement for which they are receiving the prize is over a decade in the past. I thought the Nobel prize was awarded to encourage responsible action? It's a "call to action", not a fuddy duddy pat on the back from the good-old-boys club. Look at the photo at the linked article - three white males. By the way, what the hell is up with "dividing" a Nobel prize like it's some sort

You might be thinking of the Peace Prize. The scientific ones are awarded for work which has withstood the tests of time. Without checking, I think that to get a Nobel in physics for work done a mere decade ago is unusually fast.

I get that this is the Nobel prize - but these people appear to have already accomplished something. Indeed, the noteworthy achievement for which they are receiving the prize is over a decade in the past. I thought the Nobel prize was awarded to encourage responsible action?

By the way, what the hell is up with "dividing" a Nobel prize like it's some sort of peach pie? Half for one white male, while the other two share the other half?

Not all "most important [discoveries] or [inventions] within the field of physics" - or any of the other fields for which there are Nobel prizes - can be uniquely credited to one individual. (And sometimes it's split between Asians, or between an Asian and a white guy, or....:-))

Who comes up with this stuff?

The Royal Swedish Academy of Sciences [nobelprize.org]. (Hint: you may think that as a random geek with a/. account and an opinion, you're smarter than they all are. That is not necessarily the case. HTH.)

The Royal Swedish Academy of Sciences [nobelprize.org]. (Hint: you may think that as a random geek with a/. account and an opinion, you're smarter than they all are. That is not necessarily the case. HTH.)

OTOH, it might be. As my Ph.D. advisor (Larry Biedenharn, a Nobel wannabe) used to ask me -- "How do you think they choose who gets the award?" Generally I think they do a pretty good job -- they have the same problem as the Oscar committee, they have to reward people for some specific piece of work but some people up are really being proposed (and perhaps occasionally awarded) for a lifetime of many submarginal contributions, so they'll sometimes grant a prize that at first glance seems "odd". But/. readers are a pretty well informed bunch (with a few notable exceptions, don't make me come down there and spank you) and given time to debate to a consensus would probably do just as well.

Your remarks concerning color- and gender- blindness of the committee are dead on the money; the Nobel prize goes to the physics far more than the person, and we absolutely revere physicists of any color or gender who make "great" contributions. In physics especially people just don't really give a damn; brilliance is where you find it. If there is a fault leading to a disparity in the distribution of prizes in physics, it is in the general educational and social system that feeds graduate research programs and beyond -- in the US (and probably Europe) females and certain minorities are still underrepresented in the system in spite of decades (at this point) of active recruiting. However, this really is getting better, and I'd predict that in two more decades will be a non-issue. I've seen a huge shift in the time I've been teaching physics, from having basically one black physics major every decade (first decade) to having black majors every year, including black students who top out the class with the best overall score (in damn difficult classes!). In another decade those students will come online and we'll see prizes headed that way.

Attracting female majors is still behind -- we're still a long way from 50% in the intro-majors classes I've been teaching, more like 20-25% in a good year -- but the ones we're getting are great, I've had women nailing the top THREE slots in intro physics classes total scorewise, and again I think that they are "sticking" and going on to academic careers that will eventually lead to more prizes. Our department has certainly been actively recruiting female and nonwhite faculty -- our current department chair is both female and not white, although we are probably still a decade plus away from parity due to the fact that no matter what it takes time to roll over tenured physics positions and race/gender is only ONE consideration in hiring/recruiting, secondary to competence and ability to fund research and teach and all that.

I won't say that there are no bastions of white maleness out there in physics-land, but I would say that they are a rapidly diminishing population, and that the real place changes need to take place (and are taking place) is elementary school and high school. Physics requires serious math, and there has been an enormous female anti-math social bias entrenched across the teen years forever that is just recently starting to thaw. Math majoring has gotten to where it is very nearly general balanced (still not balanced at the faculty level, though -- the same decadal lag) and I think physics is not far behind as it is now "cool" and socially "feminine" for women to be good at math in high school. I may be dead before things are really level, but my kids won't be.
rgb

Well, historically, the Nobel prize was instituted by Alfred Nobel to encourage young scientists, as far as I know. And yes, his intention was to made work possible that would not be related to weapons production etc, given his own involvement in developing dynamite - again, this is what I always understood. So that would fall under "responsible action." Over the years, the average age of Nobel Laureates has certainly gone up (I think the youngest ever was 25 years old, in 1915), so that nowadays the prize

Sorry, Coren22, for my somewhat general link; it does take a bit of clicking around.

Amounts are here [nobelprize.org]. For 2011, the full Prize amount is 10.000.000,00 SEK (Swedish Kronor); this amounts (hahah, pun intended) to Eur 1.246.401,02 or USD 1.541.050,22. I'm sure a small mansion is a possibility.

Other facts, such as the age of winners over the years, are here [nobelprize.org].

We call it the "Big Bang", but it's not really analogous to a conventional explosion like that. It's not as if the outer perimeter of space is where all the expansion is happening - space itself is expanding. Points in space - stars, planets, galaxies - are moving apart as space expands between them.

A balloon is actually one of the best analogies anyone's been able to come up with, it just gets explained badly. A balloon is a great analogy because the (2D) *surface* of the balloon acts the same way as the (3D) universe does. Expansion with no centre and everything moving away from everything else. That's why the balloon analogy is used so often and then mangled and misunderstood.

I'm probably showing my ignorance, but how do we know that the observable universe is the whole universe? What if the Big Bang, was just one of a very large number of 'local' bangs. If these other universes were far enough away, say a billion billion billion diameters of this universe, would there be any way to detect them?

If this is a possible scenario it might eliminate the conundrum of how the universe sprang into existence from nothing all those billions (but still a finite number) of years ago. A

We don't and it almost certainly isn't; certainly, I doubt many people seriously believe it is.

"What if the Big Bang, was just one of a very large number of 'local' bangs."

Something very close to this idea lies at the heart of "chaotic inflation" which is still pretty much the most widely-used version of inflationary theory. It's occasionally described as a "seething foam of spacetime" with little bubbles popping up through quantum fluctuat

In America when kids do well on something they're rewarded with a token that, while of little monetary worth, is intended to bolster their self esteem. Said child will often show this token off with pride to their parents. One such method is affix a gold-colored star on the front of a homework assignment for a job well done.

Here Riess is attributing similar affirmation of his work by the broader scientific community, which is of much more worth to him as a scientist than the monetary reward. Also, he is

It seems so often in the scientific world that two teams come to make the same discovery simultaneously. More often than not the next logical step in a field is dictated by the global advancement in that and other fields, and not the individual genius of the author. Many times ideas are ripe for the picking, if you are one of the very smart working on them. Hence the large number of joint discoveries or teams that supplement each other's results despite being in competition.

Completely off-topic, but I can't stop from making a parallel with the patent world. I expect this manner of scientific advancement to translate to technical creations too. The basis of the patent system is that rewarding the author will stimulate creativity. But one cannot wonder how many of really smart inventions wouldn't have been invented anyway, or indeed have been invented simultaneously by someone else when their time had come.

In the extreme, it's clear that a system that devotes a large proportion of the resources of society to reward the inventors in one that stimulates creativity. However that stimulus is not without his costs. The large legal ecosystem surrounding the patent system is a high consumer of those resources dedicated to inventors. Businesses have to devote important resources to ensure that are not infringing, instead of simply strive to create the best product possible. The exclusivity period is an economic disturbance, the large license fee an inventor might require for his revolutionary invention might not be earned if the same invention would have been made anyway in a year or two from the original filling date. The public key cryptography algos come to mind.

Note that I'm talking about smart, revolutionary patents. I think we can agree that the bulk of patents don't fit that category and cost the society more than they bring. Well, I'm upping the ante and question if even the smart patents really cover their costs for society. Because if most of the smart ones would have been discovered anyway in a year or two, maybe we can get rid of the patent system for good. Sure, some smart ones would remain uninvented even after the 20 years period without the stimulus of a financial prize. But I argue they would be few and far between, their opportunity cost much smaller than what we are collectively spending on the patent system.

Was reading that 'its expansion is speeding up', but I also read a document from 1972. How can they get a Nobel Prize for old news ? Here is a part of 'Siloism' (first published in Santiago de Chile, 1972).
"c) Origin of the Universe.
Light converged upon itself and this gave place to the surging of dense energetic and material expressions. This was the stage of the "fall of the light."
This provoked the original explosion, and from this centre, radiation and mass of igneous matter expanded at increasing

Finally, all bodies will end up transforming their matter into radiant energy and this energy will be converted into light. In addition, from every direction of the curved space this light will convex upon one centre in order to produce a new creative explosion. In synthesis: Light is eternal, it is the origin and the end of the Universe. It is of no interest here to study the processes of densification, nor, inversely, those of increasing vibration of matter, anti-matter, and energy. It suffices to say tha

Maybe a/.er can explain what's wrong with my theory on this... If space is a vacuum, then isnt mass just trying to spread itself out into space? Like how a water bottle caves in on itself to fill the void of someone sucking the air out of it? Why do we need Dark energy to explain it?